This very slight sketch must belong with other figure studies on folios 44, 44 verso and inside the back cover of the sketchbook (D05842, D05844, D40635). The latter three appear to be drawn by water, presumably the Thames or a tributary, and include carts or horses being watered. Hill was the first to observe their relationship to the contemporary, unfinished oil known as Men with Horses Crossing a River (Tate N02695) 1, but there seems no connection in this instance.
There are offsets or continuations of green and blue from folio 42 verso (D05840).
Martin Butlin and Evelyn Joll, The Paintings of J.M.W. Turner, revised ed., New Haven and London 1984, p.118 no.170 (pl.170).